Grip for testing-machines.



No. 759,646. PATENTED MAY 10, 1904. w. J. TRETGH.

GRIP FOR TESTING MACHINES.

APPLICATION FILED D30. 17, 1903 N0 MODEL.

Q h 1 no UNITED STATES Patented May 10, 1904.

PATENT OFFICE.

WILLIAM J. TRETGH, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO FREDERICKA. RIEHLE, OF PHILADELPHIA, PENNSYLVANIA.

GRIP FOR TESTING-MACHINES.

SPECIFICATION forming part of Letters Patent No. 759,646, dated May 10,1

Application filed December 1'7, 1903. Serial No. 185378. (No model.)

To all w/wm, it may concern:

Be it known that I, WILLIAM J. Tnnron, a citizen of the United States,residing in the city and county of Philadelphia, State of Pennsylvania,have invented a new and useful Improvement in Grips forTesting-Machines, of which the following is a specification.

My invention consists of a grip for testingmaohines. It particularlyapplies to testingmachines in which the tensility of a piece of cementor other substance is to be ascertained. It provides against a spreadingor springing open of the ends of the grip.

It further consists of novel features of construction, all as will behereinafter fully set forth.

Figure 1 of the drawings represents in front elevation a grip embodyingmy invention. Fig. 2 is a vertical section through line a", Fig. 1.

Similar numerals of reference indicate corresponding parts in thefigures.

Referring to the drawings, 1 designates the body of a grip having jaws 22 adapted to engage the test specimen. The cross bar 3, bolted to thebody 1, is provided with a center point 4, adapted to engage with thestirrup or hook through which strain is applied.

At the end of each of the jaws 2 is a roller 5, mounted on a pin 6. Asolid back 7, shown as integral with the body 1, connects the jaws 2 2and may be provided with a boss 8, against which the test specimen maybear. It will be seen that the solid back 7 acts to firmly hold the jaws2 2, so that they cannot be spread apart by any strain that can be putupon them. In the earlier forms of the devicesuch, for instance, as thatshown in United States Patent No. 657,566, granted to F. A. RiehlSeptember 11, 1900the slight spreading of the jaws which occurs whenconsiderable strains are applied to break the test-piece has seriouslyinterfered with the exactness of measurement. My invention supplies areinforcing portion, connecting thejaws beyond their juncture with thebody, by which the tendency to spread apart is entirely obviated.

It will of course be understood that the rollers 5 form no part of thepresent invention; that these may, if desired, be covered with soft orpliable material, as shown in the patent above alluded to, or they maybe dispensed with entirely, as in some earlier forms of grips. It isalso clear that the method of hanging the grip or grips, as two of theseare of course required in each testing-machine, is immaterial to myinvention that is, any other form of connection with the stirrup orclevis may be substituted for the center point 4 shown. It is also plainthat other changes may be made in my device without departing from thespirit of my invention e. g., the body 1 and crossbar 3 may of course beintegral.

The particular feature of my device is the solid-back grip in which thejaws between which the test specimen engages are connected by anintegral back or reinforcement.

Having thus described my invention, what I claim as new, anddesire tosecure by Letters Patent, is

1. In a grip for testing-machines, a body, a pair of jaws and areinforcing portion connecting said jaws beyond their juncture with saidbody, said body, jaws and reinforcing portion being integral.

2. In a grip for testing-1nachines, a body, a pair of jaws and a solidback integral with and connecting said jaws.

3. A grip for testing-machines comprising an integral body, jaws andreinforcing portions connecting said jaws beyond their juncture withsaid body, a cross-piece above said body and forming therewith a recess,and a centerpoint secured to said cross-piece and located in saidrecess.

WVILLIAM J. TRETCH.

Witnesses:

IIENRY R. FIELIS, E. J. BONSALL.

